The existing printing machines most often use photographic magazines such as described, for instance, in the U.S. Pat. No. 4,741,439. Such magazines allow an easy use of photographic printing machines since there is no need for a room in which it must be possible to establish a complete darkness any longer. However, taking into account the weight of such magazines, the length of the rolls is limited (lower than 500 m) and the magazines must be often replaced.
The applicant has developed a new type of packaging described in the French patent application filed on Jun. 8, 1990, and called "Packaging for web photographic products". Such packaging contains several webs of photosensitive product wound around tube expanders resting on a spindle, each roll having a length of possibly 1500 m approximately, or more. As set forth in the application mentioned earlier, this type of packaging is fitted with several light-tight slots through which the photosensitive webs can be pulled out.
However, owing to the great length of each of the wound webs, and, consequently, to the roll weight, there are high friction forces. In view of this, the tension force required to pull the web out of this type of packaging is greater than the tension force required to pull webs out of photographic magazines with a relatively small capacity available off the shelf at this time. This phenomenon prevents the available printing machines from being directly connected to the new type of packaging since the tension force exerted by the printing machine feeding device has not a value high enough for the time being.
Moreover, during the feeding of the photographic webs from the packing to the printer, the length of the photographic web which is fogged has to be limited to its minimum. An object of the invention is an interface device liable to be adapted to the packaging described in the French patent application filed on Jun. 8, 1990, and called "Packaging for web photographic products".
The abstract of JP-A-58108663 published on Jan. 8, 1985 describes a device which renders the feeding of the paper independant of inertia resistance and frictional forces applied by the feeding roller. This device allows the formation of a paper loop so as to avoid inertia resistance from breaking the paper weg during the feeding operation.
Document DE-A-3,034,083 describes a processing device wherein a loop is formed between the paper cassette and the entry slot of the processing device. Said loop is regulated through photocell means.
Document U.S. Pat. No. 4,429,988 describes a photographic printer wherein the web travels along a track having loops so as to render substantially independent the functionning of the various device acting on the web.
Another object of the invention is an interfacing device which not only eliminates the influences of various forces on the web to move it but also prevents, at the same time, the fogging of the photographic web along an important length during the introduction of the leading edge of the web in the printer, said introduction being substantially automated.